A recorded message played that included the drill language, “Exercise, exercise, exercise.” However, the message also erroneously contained the text for a live ballistic missile alert, saying, “This is not a drill.”

Other workers heard the message on a speakerphone. While they knew it to be a drill, the FCC says the employee who issued the false alert “claimed to believe” it was a real emergency and issued the alert.

That officer, who has not been identified, has refused to co-operate in the investigation beyond providing a written statement.

The alert was sent to cellphones, TV and radio stations in Hawaii, leading people to fear the state was under nuclear attack. It took 38 minutes for officials to send an alert retracting the warning.